New device uses carbon nanotubes to rate chillis' hotness

London, May 13 : Scientists have developed a new device that takes the help of carbon nanotubes to provide an objective and cost effective way to rate how hot a particular chilli is.

According to a report in Nature News, Richard Compton, a chemist at the University of Oxford, UK, and his colleagues have made the device, which measures the accumulated concentrations of the capsaicins in a chilli simultaneously.

Capsaicins are chemicals, which cause the hotness in a chilli. The higher the concentration, the hotter a chilli tastes.

The conventional method to determine the heat of a chilli or chilli sauce was devised in 1912 by chemist Wilbur Scoville.

Scoville ratings are worked out by diluting a chilli-containing sauce to the point at which a team of five expert tasters can no longer detect the heat.

But Richard Compton and his colleagues have developed a way to get a Scoville rating for a sauce while sparing the tasters' tongues, and without blowing a cook's budget.

The device that they have developed measures the accumulated concentrations of the capsaicins in a chilli simultaneously.

The technique involves coating electrodes covered in carbon nanotubes with the chilli sample. The nanotubes have a high surface area, which means that they can absorb lots of the sample.

The whole device is then dunked in an ethanol-based solution to oxidize the capsaicins, which causes current to flow.

"Stronger chillies mean more electric current," said Compton.

According to Compton, his method is cheaper than the only other available tester-free method, called high-pressure liquid chromatography (HPLC).

The HPLC technique involves separating out the capsaicins in a sauce and working out their concentrations individually - an expensive process.

By using mass-producible electrodes screen-printed with carbon nanotubes, Compton reckons he can bring down the cost of a sampler to around 30 pounds. By comparison, an HPLC machine costs around 40,000 pounds.

Compton has applied for a patent for his device and is attracting commercial interest for what he envisages as a cheap, disposable hand-held heat detector that keen cooks could use in their own kitchens.